分类： 光学 >> 量子光学 提交时间： 2023-02-19
Jingwen Ma
Taojie Zhou
Mingchu Tang
Haochuan Li
Zhan Zhang
Xiang Xi
Mickael Martin
Thierry Baron
Huiyun Liu
Zhaoyu Zhang
Siming Chen
Xiankai Sun
摘要： Robust laser sources are a fundamental building block for contemporary information technologies. Originating from condensed-matter physics, the concept of topology has recently entered the realm of optics, offering fundamentally new design principles for lasers with enhanced robustness. In analogy to the well-known Majorana fermions in topological superconductors, Dirac-vortex states have recently been investigated in passive photonic systems and are now considered as a promising candidate for single-mode large-area lasers. Here, we experimentally realize the first Dirac-vortex topological lasers in InAs/InGaAs quantum-dot materials monolithically grown on a silicon substrate. We observe room-temperature continuous-wave single-mode linearly polarized vertical laser emission at a telecom wavelength. Most importantly, we confirm that the wavelength of the Dirac-vortex laser is topologically robust against variations in the cavity size, and its free spectral range defies the universal inverse scaling law with the cavity size. These lasers will play an important role in CMOS-compatible photonic and optoelectronic systems on a chip.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： The textbook-accepted formulation of electromagnetic force was proposed by Lorentz in the 19th century, but its validity has been challenged due to incompatibility with the special relativity and momentum conservation. The Einstein-Laub formulation, which can reconcile those conflicts, was suggested as an alternative to the Lorentz formulation. However, intense debates on the exact force are still going on due to lack of experimental evidence. Here, we report the first experimental investigation of angular symmetry of optical force inside a solid dielectric, aiming to distinguish the two formulations. The experiments surprisingly show that the optical force exerted by a Gaussian beam has components with the angular mode number of both 2 and 0, which cannot be explained solely by the Lorentz or the Einstein-Laub formulation. Instead, we found a modified Helmholtz theory by combining the Lorentz force with additional electrostrictive force could explain our experimental results. Our results represent a fundamental leap forward in determining the correct force formulation, and will update the working principles of many applications involving electromagnetic forces.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： The modern information networks are built on hybrid systems working at disparate optical wavelengths. Coherent interconnects for converting photons between different wavelengths are highly desired. Although coherent interconnects have conventionally been realized with nonlinear optical effects, those systems require demanding experimental conditions such as phase matching and/or cavity enhancement, which not only bring difficulties in experimental implementation but also set a narrow operating bandwidth (typically in MHz to GHz range as determined by the cavity linewidth). Here, we propose and experimentally demonstrate coherent information transfer between two orthogonally propagating light beams of disparate wavelengths in a fiber-based optomechanical system, which does not require any sort of phase matching or cavity enhancement of the pump beam. The coherent process is demonstrated by phenomena of optomechanically induced transparency and absorption. Our scheme not only significantly simplifies the experimental implementation of coherent wavelength conversion, but also extends the operating bandwidth to that of an optical fiber (tens of THz), which will enable a broad range of coherent-optics-based applications such as optical sensing, spectroscopy, and communication.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Nonlinear topological photonic and phononic systems have recently aroused intense interests in exploring new phenomena that have no counterparts in electronic systems. The squeezed bosonic interaction in these systems is particularly interesting, because it can modify the vacuum fluctuations of topological states, drive them into instabilities, and lead to topological parametric lasers. However, these phenomena remain experimentally elusive because of limited nonlinearities in most existing topological bosonic systems. Here, we experimentally realized topological parametric lasers based on nonlinear nanoelectromechanical Dirac-vortex cavities with strong squeezed interaction. Specifically, we parametrically drove the Dirac-vortex cavities to provide phase-sensitive amplification for topological phonons, and observed phonon lasing above the threshold. Additionally, we confirmed that the lasing frequency is robust against fabrication disorders and that the free spectral range defies the universal inverse scaling law with increased cavity size, which benefit the realization of large-area single-mode lasers. Our results represent an important advance in experimental investigations of topological physics with large bosonic nonlinearities and parametric gain.
分类： 光学 >> 量子光学 提交时间： 2023-02-19
摘要： Novel physical concepts that originate from quantum mechanics, such as non-Hermitian systems (dealing mostly with PT and anti-PT symmetry) and bound states in the continuum (BICs), have attracted great interest in the optics and photonics community. To date, BICs and anti-PT symmetry seem to be two independent topics. Here, we for the first time propose a parallel cascaded-resonator system to achieve BICs and anti-PT symmetry simultaneously. We found that the requirements for the Fabry-P\'erot BIC and anti-PT symmetry can both be satisfied when the phase shift between any two adjacent resonators is an integer multiple of {\pi}. We further analyzed the cascaded-resonator systems which consist of different numbers of resonators and demonstrated their robustness to fabrication imperfections. The proposed structure can readily be realized on an integrated photonic platform, which can have many applications that benefit from the advantages of both BICs and anti-PT symmetry, such as ultralow-linewidth lasing, enhanced optical sensing, and optical signal processing.
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